Mechanical toothbrush



Dec. 8, 1964 Filed April 16, 1962 F. H. RASMUSSEN MECHANICAL TOOTHBRUSH 2 Sheets-Sheet l INVENTOR. :7ram%?asmussm BY W Mm ATZ'KS.

Dec. 8, 1964 F. H. RASMUSSEN MECHANICAL TOOTHBRUSH 2 Sheets-Sheet 2 Filed April 16, 1962 FIGS F165 United States I Patent Oil ice 3,159,859 ll/ECHANICAL TQOTHBRUSH Frank H. Rwmussen, 744 S. pring Ave,

La Grange, ill. Filed Apr. 16, 1962, Ser. No. 187,531 4 Claims. (Cl. 15--22) This invention relates in general to mechanical toothbrushes, and is directed more particularly to mechanical toothbrushes which are electrically operated, and in which the brush element thereof has a path of movement which combines rotary and reciprocating motions.

It is common knowledge that dentists recommend that the teeth be brushed in a movement which begins with the gums and ends with the biting edge of the teeth. That is to say, when teeth are manually brushed, the brush will be held in such a position that it will first contact the gums and then the brush will be moved in a direction toward the biting edge of the teeth. After it has completed this movement, the brush is then moved away from the teeth and is then brought again into contact with the gums and the motion is repeated.

Although dentists usually concur that this is the ideal brushing technique, nevertheless, many people do not follow it when they brush their teeth manually. Obviously, therefore, if-this motion can be duplicated by mechanical means, this proper brushing technique can be performed more elfectively and more efficiently because of the positive control thus assured.

Heretofore, many different forms of mechanical toothbrushes have been known. Some of these brushes utilized a reciprocating motion by itself. This, of course, hasthe disadvantage that the brush element will move first from the gum toward the biting edge of the tooth and then back again, forcing food particles back between the teeth at the gum line and up under the gums, thereby defeating the purpose of the original motion. Another form involved the use of a brush element which was circular in cross section and which rotated continuously in the same direction. .This would produce the desired result, but it was found that the brush element and the mechanism required to drive it was too expensive for any practical purpose.

Still another form of toothbrush of the mechanical type which has heretofore been known utilized an oscillatingmotion of the brush. Here again, however, when the brush element moves in an arcuate path in one direction, it cleans from the gum toward the tooth, but when it returns, it then brushes in the opposite direction, and thereby defeats the purpose for which the toothbrush was designed.

In view of the foregoing, therefore, the present invention is designed so that the driving means for the brush element will generate a path of movement which combines the rotary with the reciprocating. Sucha path of movement causes the brush first to begin at the gum and move toward the biting edge of the tooth, and thereafter to move away from the tooth and back to the gum again without touching the gum or tooth in its return move-- ment.

It is therefore, one of the primary objects of the present invention to provide a mechanical toothbrush which overcomes the objections in brushes heretofore known. 7 Another object of the present invention is to provide, in a mechanical toothbrush, drive means which will produce a combination of a rotary or arcuate motion with a reciprocating'movement of the brush element. i

I Still another and more specific object of the invention is to provide a mechanical toothbrush having a housing within which mechanism is provided to impart a reciprocating motion to the brushelement, and wherein intermediate the ends of the handle of the brush, there is pro- Vided additional means to modify the normally reciproeating movement of the brush element thereby to generate a path of movement which combines the circular or arcuate motion with the reciprocating motion, thus resulting in a movement of the brush from the gum to the biting edge of the tooth then outwardly away from the tooth and back to the gum again. 7

Still another and specific object of the invention is to provide a mechanical toothbrush having a housing within which the drive means for the brush element is located and which has as a part thereof, a stationary guard or shield, which is so designed and positioned to protect the lip of the user from the movement of the brush element.

A further and more specific object of the invention is to provide a mechanical toothbrush having a housing within which there is an elastic or resilient partition which 1 enables movement of the handle or shank in a combined section, of the mechanical toothbrush which forms a part of the present invention;

FIG. 2 is an elevational view of the brush element and handle attached thereto with a part of the housing broken away to show some of the details of the drive mechanism;

FIG. 3 is a horizontal sectional view taken substantially.

along the'plane of line 33 of FIG. 2;

FIG. 4 is a fragmentary 'elevational view looking toward the brush element;

FIG. 5 is a horizontalsectional View taken substantially along the plane of line 555 of FIG.'2; H FIG. 6'is' a view similar to FIG. 5, but showing a modified form of the pin and slot connection which modifies the reciprocating movement of the brush element;

FIG. 7 is a diagrammatic elevational view of a brush and handle element of the present invention, but showing a modified form of the slot in the brush handle, which modifies the reciprocatingmovement of the brush, and

generates a different path of movement than that shown in FIGS. 1 and 2; 1

FIG. 8 is also a diagrammatic view similar to FIG. 7,

but showing a still further modified form of the slot in the brush handle; and

FIG. 9 is a view similar to FIGS. Tand S, but showing a still further modified form of slot inthe brush handle thereby to impart a different path of movement to the brush element.

Referring now more particularly to the drawings, and especially to FIGS. 1 and 2, the housing is illustrated by the numeral 1'. In this housing there is provided any suitable and well-known source of power generally indicated by the numeral 2. This source of power forms no I the housing has rotatably mounted thereon a bevel gear i 6. This bevel gear 6 is in mesh with the pinion 4 so that when the drive or motive means 2 is in operation, rotation of the shaft 3 and pinion 4 will cause rotation of the bevel ear 6. r

The bevel gear 6 has in'ounted at one side thereof a pin 7 to which the handle dot the toothbrush itself is piv Patented Dec. 8, i964 a otally secured. Thus far then, it will be seen that rotation of the gear 6 will act as a crank to impart a reciprocating movement to the handle 8 and to the brush element at the outer end thereof generally indicated by the numeral 9.

At a suitable point within the housing 1, there is a partition member 10 preferably formed of an elastic or a resilient material. This partition 10, in the specific form shown herein, has a suitable opening therein through which the handle 8 of the toothbrush element passes inwardly to the housing. The partition 16, being formed of a resilient material, will permit reciprocation or other equivalent type of movement to be imparted to the brush and its handle 8 without interfering with the function thereof.

The function of the partition 10 is primarily to prevent moisture, tooth paste or other undesirable elements from reaching the gears and drive means located within the housing and on the inner side of the partition.

Intermediate the ends of the brush handle 8, there is provided a slot or groove indicated by the numeral 11. A pin 12 extending inwardly of the housing passes into or through the slot 11. This combination of slot 11 and pin 12 acts to modify the normally reciprocating movement of the handle 8 and brush 9 imparted thereto by the rotary movement of the gear 6.

The slot 11 may assume any one of a number of different configurations and still produce the desired result in the path of movement of the brush element. In FIG. 2 of the drawings, it will be noted that the slot 11 assumes a somewhat S-shape. When the gear 6 rotates in a counterclockwise direction, thereby acting as a crank upon the innermost end of thebrush handle 8, the reciprocating movement thus imparted to the handle and the brush element 9 will be modified by the pin and slot arrangement indicated at 12 and 11 respectively, so as to generate a path of movement substantially like that shown in FIGS.,1 and 2 by the dotted line indicated at 13. In FIG. 2, the dotted line position of the brush and brush handle is that which the brush will assume at approximately 180 from that shown in the solid line position thereof.

Thus, as ,far as FIGS. 1 and 2 of the drawings are concerned, there is also illustrated a part of the face of a user showing a tooth 14 and the gum 15. The lip of the user is shown at 16 and the nose at 17. Thus, this portion of the face as illustrated in these figures will aid in properly orienting the teeth and gums of the user with respect to the brush element, so that it will be seen that the tooh and gum shown are in the upper part of the users mouth.

With the arrangement of the parts shown in FIGS. 1 and 2, it will be evident that the brush element has a somewhat clockwise movement. This path of movement, however, is a combination arcuate or rotary movement with the reciprocating movement. During the path of movement as illustrated at 13, it will be seen that the brush begins at the gum line and then moves downwardly across the outer surface of the tooth toward the biting edge 18 thereof. This path of movement, then, is such that the brush element thereafter moves outwardly away from the tooth and gum and then upwardly again until it moves toward the right into contact with the gum, at which point it again begins the downward movement toward the biting edge of the tooth.

Referring to FIG. 1, it will be noted that at one end of the housing 1 there may be provided if desired, an elongated extension indicated at 19. This extension 1? is curved over the brush element at its outer end and acts as a guard means. This guard, then, serves three purposes. One is to move the lip out of the way and hold it there so that the brush element will not contact it and thereby cause discomfort. Another purpose is to prevent the tooth paste from being spattered about since it will be confined to the inner surface of the shield 19. This shield partially surrounds the brush handle 8 so that it will have an open side toward the brush handle. A third purpose is to position the brush element so that the proper cleaning action is achieved. In other words, that part of the guard 20 which forms the edge around the upper part of the open side may be held so that it contacts the gum of the user, thereby preventing the user from pressing the brush element against the teeth too hard and insuring that on the return stroke thereof the brush element will be out of contact with the teeth so that the benefit of brushing away from the gum will not be interfered with.

This guard member may assume any desirable configuration and one form thereof in the front elevational view may be like that shown in FIG. 4 of the drawings.

From the foregoing, it will be seen that the path of movement of the brush element, which is generated by the drive means and the pin and slot connection intermediate the ends of the brush handle, is of the nature of a modified oval or circle. In this connection, it should be made clear at this point that the specific path of movement is unimportant, as long as the drive means is designed to cause the brush to begin its movement at the gum line and then move toward the biting edge of the tooth, and thereafter to move away from the gum and tooth back to the beginning of the path of movement. The elongated S-shaped slot 11, as shown in FIG. 2 combined with the circular movement generated by the gear 6 will cause the brush element to be moved in a path like that shown at 13.

Referring now to FIG. 7 of the drawings, the gear 6 is shown diagrammatically and the brush handle 8 is shown pivotally connected thereto by the pin 7, exactly like that heretofore described with respect to FIGS. 1 and 2. The only difference in the construction of FIG. 7 and that heretofore described, is in the shape of the slot, which, in FIG. 7, will be indicated by the numeral 11a. In this case, the slot is straight and is positioned at an angle with respect to the axis of the brush handle. This slot, with the pin 12 in its normal position as heretofore described, and with the circular movement of the gear 6, which acts as a crank upon the brush handle, will impart to the brush 9 a modified reciprocating motion. The path of movement of the brush element thus generated by this combination of elements is shown at 13a. This path is somewhat similar to the path 13 shown in FIGS. 1 and 2, except that the eliptical path thereof is more arcuate. The important point is, however, that even in this path of movement, the brush still is caused to move from the gum toward the biting edge of the tooth, then away from the tooth and back to the gum again.

Referring now to FIG. 8, again there is illustrated in diagrammatic fashion, the gear 6, pivot pin 7 and brush handle 8. In this instance, however, the slot also is of an S-shape configuration, but is positioned in the handle reverse to that shown in FIG. 2. This slot is identified in FIG. 8 as 11b. With this combination of elements, movement of the brush 9 will follow a path like that shown in the dotted lines indicated by the numeral 13b. It will be obvious that this path of movement is slightly different from those heretofore discussed with respect to FIGS. 1, 2 and 7, but the movement of the brush still is from the gum to the biting edge of the tooth, then outwardly, and back to the gum again.

In FIG. 9, the slot in the brush handle 8 is indicated by the numeral and constitutes a straight slot substantially parallel to the axis of the brush handle 8. In this instance, the normal reciprocating movement of the brush 9 caused by the crank motion as between the gear 6 and the end of the brush element 8 is modified, due to the pin 12 in the slot lie, so that a path of movement like that shown by the dotted line at is produced. In this particular instance, the path of movement will be more circular than those heretofore descn'bed.

It will thus be evident that the actual shape of the slot in the brush handle, which cooperates with the pin 12 to create these various paths of movement, may assume different specific shapes, as long as the desired result is obtained. This desired result, of course, is the movement of the brush element downwardly or upwardly,

as the case may be, from the gum to the biting edge of the teeth and then outwardly away from the teeth and back to the beginning of the path of movement again.

In FIGS. 1 and 2, the pin 12 is illustrated as protruding into the slot 11. In FIGS. 5 and 6, however, modified forms of this connection are shown. V

In FIG. 5, instead of the slot 11 extending through the brush handle, there is provided a pair of grooves 21 and 21a at opposite sides of the handle 8. In this construction, pins 22 and 22a extend inwardly from opposite sides of the housing 1, so that the inner ends thereof will extend into the respective slots 21 and 21a. .Thus, the same result will be obtained with this specifically different construction of pin and slot connection.

In FIG. 6, the brush handle 8 is shown as having the slot 23 extending therethrough. A pin 24 passesthrough the slot 23 from one side of the housing to the other. In this case, the pin 24 is shown as having flanges 25 and 25a thereon adjacent oppositesides of the brush handle 8.

If desired, the brush handle 8 may be formed in two parts as more clearly shown in FIG. 1. In this instance, the outer end of the brush handle 8 may be separable from the remainder thereof. This outer end is indicated in FIG. 1 by the numeral 8a and is provided at the inner end thereof with an extension 26. The inner part: of the brush handle 8 is provided with a suitable recess 27 adapted to receive the projection 26 on the outer portion 8a, thereby enabling such outer portion to be removable from the inner portion so that the brush element itself may be changed from time to time. It will, of course, be evident to those skilled in the art that a reverse arrangement will operate the same way and is within the scope of the present invention, i.e., the pin may be on the barn dle and extend into a slot in the housing.

From the foregoing, it will therefore be evident that the present invention provides a mechanical toothbrush having numerous advantages over those heretofore known in the prior art.

nected to the inner end of said handle and operable to impart a reciprocating motion to said brush, and

(d) means intermediate the ends of said handle and including a pin and a substantially S-shaped slot connection between said housing and brush handle to modify the reciprocating motion imparted by said drive means, said slot extending generally longitudinally of said handle, thereby to generate a combination rotary and reciprocating path of movement for said brush, whereby, when the handle is positioned vertically with the work contacting portion of the brush against the users teeth, the brush will move from the users gum toward the biting edge of the teeth, then away therefrom out of contact therewith and back to the gum.

2; A mechanical toothbrush comprising (a) a housing (b) a brush handle having an inner endwithin said housing and an outer end extending outwardly from said housing and having a brush on the outer end thereof,

(0) a resilient partition in said housing intermediate the ends of said brush handle,

(d) eccentric drive means within said housing connected to the inner end of said handle and operable to impart a reciprocating motion to said brush, and

'(e) means intermediate the ends of said handle and including a pin and a substantially S-shaped slot connection between said housing and brush handle to modify the reciprocating motion imparted thereto by said drive means, said slot extending generally longitudinally of said handle, thereby to generate a combination rotary and reciprocating path of movement for said brush, whereby, when the handle is positioned vertically with the work contacting portions of the brush against the users teeth, the brush will move from the users gum toward the biting edge of the teeth, then away therefrom out of contact therewith and back to the gum.

3. A mechanical toothbrush according to claim 1 wherein said substantially S-shaped slot is located in said handle, and the cooperatingpin is positioned on said housing.

4; A mechanical toothbrush according to claim 2 wherein said substantially S-shaped slot is in said handle and the cooperating pin is positioned on said housing.

References Cited in the file of this patent UNITED STATES PATENTS 1,255,028 Leonard et a1 Ian. 29, 1918 2,044,863 Sticht June 23, 1936 2,095,956 Bess Oct. 19, 1937 2,372,731 Nalbach et a1. Apr. 3, 1945 2,644,972 Ubel July 14, 1953 

1. A MECHANICAL TOOTHBRUSH COMPRISING (A) A HOUSING (B) A BRUSH HANDLE HAVING INNER AND OUTER ENDS THEREON AND EXTENDING OUTWARDLY FROM SAID HOUSING AND HAVING A BRUSH ON THE OUTER END THEREOF, (C) ECCENTRIC DRIVE MEANS WITHIN SAID HOUSING CONNECTED TO THE INNER END OF SAID HANDLE AND OPERABLE TO IMPART A RECIPROCATING MOTION OT SAID BRUSH, AND (D) MEANS INTERMEDIATE THE ENDS OF SAID HANDLE AND INCLUDING A PIN AND A SUBSTANTIALLY S-SHAPED SLOT CONNECTION BETWEEN SAID HOUSING AND BRUSH HANDLE TO MODIFY THE RECIPROCATING MOTION IMPARTED BY SAID DRIVE MEANS, SAID SLOT EXTENDING GENERALLY LONGITUDINALLY OF SAID HANDLE, THEREBY TO GENERATE A COMBINATION ROTARY AND RECIPROCATING PATH OF MOVEMENT FOR SAID BRUSH, WHEREBY, WHEN THE HANDLE IS POSITIONED VERTICALLY WITH THE WORK CONTACTING PORTION OF THE BRUSH AGAINST THE USER''S TEETH, THE BRUSH WILL MOVE FROM THE USER''S GUM TOWARD THE BITING EDGE OF THE TEETH, THEN AWAY THEREFROM OUT OF CONTACT THEREWITH AND BACK TO THE GUM. 